Fine composite mask for glass substrate support

Abstract

A glass substrate supported fine composite mask (GS-FHM) for OLED display manufacturing is disclosed. The mask includes at least one layer of open hole metal layer and at least one layer of open hole ceramic layer to improve mechanical stability and pattern accuracy. The glass substrate provides structural support for the mask and is selectively removed within the display area to form a self-supporting structure. The open hole ceramic layer has excellent shape retention and can maintain the accuracy of the open hole, but has high brittleness; the open hole metal layer has good stress absorption capacity and can reduce the risk of rupture, but is prone to plastic deformation. By combining the high stability of the ceramic layer and the mechanical durability of the metal layer, the GS-FHM can improve the deposition accuracy of OLED materials and improve the long-term reliability of the mask. The mask is suitable for microOLED ultra-fine pattern deposition and AMOLED large-area deposition process, providing a high-resolution, high-stability and scalable manufacturing solution.

Description

Technical Field

[0001] This invention relates to fine masking technology for the manufacture of organic light-emitting diode (OLED) displays, particularly a glass substrate-supported fine composite mask (GS-FHM) comprising an open-cell composite layer integrating ceramic and metal materials. This mask is suitable for high-precision RGB pixel deposition in various OLED display applications, including microOLED and AMOLED production. Background Technology

[0002] Glass-substrate supported fine metal mask (GS-FMM) and glass-substrate supported fine ceramic mask (GS-FCM) have been proposed in Taiwan patent applications 113209991 and 113212607, aiming to improve upon traditional Invar sheet substrate fine metal mask (FMM) technology. By introducing a glass substrate as a support layer, these technologies significantly improve the stability and alignment accuracy of apertures, and to some extent overcome the mechanical limitations of traditional FMMs.

[0003] GS-FMM (Glass Substrate Supported Fine Metal Mask, Taiwan Patent 113209991) consists of an aperture metal layer (such as Invar, Nickel, or Alloy 42) and a glass substrate. Supported by the glass substrate, GS-FMM possesses moderate mechanical flexibility, reducing aperture misalignment during OLED material deposition. However, after the glass substrate is removed, the aperture metal layer loses its support and becomes susceptible to plastic deformation and creep effects. As the metal layer thins and the display area increases, it is prone to wrinkling, sagging, and long-term shape distortion, thereby reducing the consistency of the OLED manufacturing process.

[0004] GS-FCM (Glass Substrate Supported Fine Ceramic Mask, Taiwan Patent 113212607) uses ceramic materials such as silicon nitride (Si3N4) and alumina (Al2O3) to improve the shape retention of openings. Ceramic materials possess high rigidity and extremely low creep, enabling GS-FCM to maintain long-term dimensional stability during repeated OLED material deposition cycles. However, ceramic materials are brittle and lack ductility, making them prone to cracking or even breakage due to mechanical impact or thermal cycling stress. As the opening ceramic layer becomes thinner and the display area increases, its mechanical strength further decreases, limiting the application of GS-FCM.

[0005] Although GS-FMM and GS-FCM each offer certain advantages, their structural characteristics still pose challenges to the long-term reliability of OLED manufacturing.

[0006] In GS-FMM, plastic deformation of the aperture metal layer causes the aperture shape to gradually change over time, and this is further deteriorated by creep during OLED deposition. Furthermore, during the fabrication of the metal mask, the release of internal stress when the glass substrate is removed can lead to permanent misalignment of the aperture, thus affecting the consistency of OLED pixel deposition.

[0007] In GS-FCM, while the perforated ceramic layer possesses high rigidity, ensuring the stability of the perforation shape, its lack of plastic deformation capability makes it susceptible to cracking under mechanical impact or thermal stress, ultimately leading to fracture and affecting the integrity of the perforation. This mechanical brittleness limits the applicability of GS-FCM. Under the stress of material handling and the high precision requirements of large-size OLED manufacturing, higher structural strength is still needed to ensure long-term stability.

[0008] Therefore, while GS-FMM and GS-FCM offer significant technological advantages, they still have limitations in mechanical durability, dimensional stability, and long-term process reliability. It is necessary to develop a hybrid mask technology that integrates the advantages of metals and ceramics to overcome these shortcomings, thereby improving its applicability and process stability. Summary of the Invention

[0009] To overcome the limitations of GS-FMM and GS-FCM, this invention proposes a glass substrate supported fine composite mask (GS-FHM), which includes an open-cell composite layer, optimizes mechanical stability and process compatibility, and is suitable for OLED manufacturing.

[0010] In microOLED applications, the ultra-high resolution requirements necessitate an open-cell composite layer thickness of less than 10µm. Thin open-cell metal layers are prone to plastic deformation, while thin open-cell ceramic layers are easily fractured due to their high brittleness, leading to structural failure. GS-FHM effectively solves these problems by combining the shape retention of open-cell ceramic layers with the ductility of open-cell metal layers through an open-cell composite layer, ensuring both durability and precision.

[0011] In large-size AMOLED display applications, maintaining the stability of the perforated composite layer on large-area glass substrates (such as Gen8 glass substrates, 2200mm × 2500mm) is crucial. The perforated composite layer structure of GS-FHM prevents deformation, sagging, and stress damage, ensuring the accuracy and stability of large-area OLED material deposition.

[0012] The mechanical balance between the open-cell ceramic layer and the open-cell metal layer is crucial for controlling plastic deformation. The open-cell ceramic layer has low plasticity, which prevents warping and maintains precise open-cell geometry; while the open-cell metal layer has high ductility, which absorbs mechanical stress, prevents sudden fracture, and enhances structural strength.

[0013] The role of the perforated ceramic layer in GS-FHM is crucial for mitigating stress deformation. During manufacturing, when the glass substrate is etched away from the back side, the perforated metal layer may wrinkle, bend, or warp due to internal stress release if there is a lack of additional structural support. The perforated ceramic layer stabilizes the structure, prevents severe deformation, and ensures dimensional stability. During use, the perforated metal layer is susceptible to creep and accumulated plastic strain, leading to gradual misalignment of the openings; however, the perforated ceramic layer does not undergo plastic flow and can act as a structural stabilizer, maintaining the accuracy and stability of the openings throughout the long-term OLED manufacturing process.

[0014] The GS-FHM's aperture composite layer enables high-precision aperture formation, ensuring accurate OLED pixel deposition and reducing deformation. Furthermore, GS-FHM offers excellent process scalability, making it suitable for high-volume production of microOLED and AMOLED, ensuring high yield and efficient manufacturing.

[0015] By integrating the low plasticity of the perforated ceramic layer with the moderate ductility of the perforated metal layer, GS-FHM significantly improves mask performance, deposition accuracy, and mechanical reliability. The optimized design of the perforated composite layer ensures high mechanical durability and perforation shape accuracy, effectively overcoming the deformation issues of GS-FMM and the brittleness of GS-FCM. This technological innovation provides a high-precision and scalable OLED manufacturing solution, ensuring process stability and high yield, suitable for various OLED applications requiring ultra-fine patterning and large-area, high-precision deposition. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of GS-FMM, which includes a glass substrate, an electrode metal layer, and an opening metal layer, used for OLED material deposition.

[0017] Figure 2 This is a cross-sectional view of the GS-FCM, showing the glass substrate and the perforated ceramic layer to ensure the stability and durability of the perforation shape.

[0018] Figure 3 This represents the strain hardening index n, creep resistance, and coefficient of thermal expansion for metallic and ceramic materials.

[0019] Figure 4 This is a cross-sectional view of the GS-FHM, showing its double-layer and triple-layer structure, designed to balance mechanical stability and stress absorption capacity.

[0020] Figure 5 This is a cross-sectional view of the GS-FHM, which includes a three-layer and multi-layer structure to further improve the accuracy and durability of the opening shape.

[0021] Figure 6(Example 1) is the manufacturing process of GS-FHM, used to form right-angle openings.

[0022] Figure 7 (Example 2) is the first part of the GS-FHM manufacturing process, used to form a negative cone angle opening.

[0023] Figure 8 (Example 2) is the second part of the GS-FHM manufacturing process, used to complete the negative cone angle opening.

[0024] Figure 9 (Example 3) is the first part of the alternative GS-FHM manufacturing process, used to form negative cone angle openings.

[0025] Figure 10 (Example 3) is the second part of the alternative GS-FHM manufacturing process, used to complete the negative cone angle opening.

[0026] Figure 11 (Example 4) is the first part of an alternative GS-FHM manufacturing process for forming negative cone angle openings.

[0027] Figure 12 (Example 4) is the second part of an alternative GS-FHM manufacturing process used to complete the negative cone angle opening. Detailed Implementation

[0028] Figure 1 A fine metal mask supported by a glass substrate (GS-FMM) is described, which includes a glass substrate 13, an electrode metal layer 14 and an opening metal layer 15. Figure 1 A shows a top view of the display area 12 and the non-display area 11, which includes precisely patterned openings for OLED material deposition. Figure 1 B shows an enlarged cross-sectional view of the aperture metal layer 15 deposited on the electrode metal layer 14, with the electrode metal layer 14 in direct contact with the glass substrate 13.

[0029] During the manufacturing process, the GS-FMM structure maintains dimensional stability through the glass substrate 13 to prevent warping and shrinkage of the aperture metal layer 15. However, after removing the glass substrate 13, the structural stability of the electrode metal layer 14 and the aperture metal layer 15 decreases, making them susceptible to stress relaxation, plastic deformation, and creep, which leads to changes in the geometry of the apertures, thereby affecting the OLED deposition accuracy and overall manufacturing yield.

[0030] Figure 2A glass-substrate supported fine ceramic mask (GS-FCM) is described, which uses an open-cell ceramic layer 16 as the main opening definition layer. Compared to GS-FMM, it has higher opening shape stability, but its mechanical stress absorption capacity is reduced. Similar to GS-FMM, GS-FCM includes a glass substrate 13 as structural support. Figure 2 A's top view and Figure 1 Similar to structure A, display area 12 is surrounded by non-display area 11. Figure 2 The cross-sectional view of B shows that the perforated ceramic layer 16 serves as the main perforation definition layer to ensure perforation accuracy.

[0031] GS-FCM enhances the shape stability of the apertures by utilizing the low plasticity of the aperture ceramic layer 16, preventing shape changes over time. However, ceramic materials are inherently brittle and prone to cracking or fracture when subjected to mechanical stress or thermal cycling. Furthermore, the aperture ceramic layer 16 lacks ductility and cannot effectively absorb mechanical stress, making it susceptible to breakage during handling and repeated OLED deposition cycles. These limitations reduce the long-term durability and mechanical stability of GS-FCM; therefore, its mask lifetime needs further improvement when applied to OLED manufacturing environments requiring high long-term reliability.

[0032] Figure 3 Data on strain hardening index (n-value) for various metal and ceramic materials are provided. This index is an important parameter for evaluating material behavior in OLED mask applications, and it particularly affects the long-term stability and durability of the perforated metal layer 15 and the perforated ceramic layer 16.

[0033] Figure 3 The listed metals, such as Invar, Super Invar, and Nickel, exhibit moderate strain hardening (n = 0.2–0.4), indicating that they can increase strength and redistribute stress after plastic deformation, reducing the risk of immediate fracture. However, Figure 3 The results show that metals with higher n values, such as nickel (n=0.34) and Kovar (n=0.3), are more prone to gradual plastic deformation, causing the aperture metal layer 15 to deform over time. In OLED mask applications, this deformation can lead to aperture misalignment, especially after the glass substrate 13 is removed.

[0034] Figure 3The listed ceramic materials, such as silicon nitride (Si3N4) and alumina (Al2O3), have n values ​​close to zero, indicating that they will not undergo plastic deformation but will remain rigid until the fracture limit is reached. While this ensures long-term retention of the open-pore shape, ceramic materials are highly brittle and lack stress absorption capacity. When subjected to mechanical stress, cracks may propagate rapidly and cause sudden fracture. This suggests that although the open-pore ceramic layer 16 can maintain the accuracy of the open-pore structure, it may still be damaged under mechanical stress.

[0035] Since the perforated metal layer 15 may gradually deform over time, and the perforated ceramic layer 16 is prone to cracking due to brittleness, using either material alone still has limitations in terms of high precision and long-term stability, and it is difficult to simultaneously achieve both shape retention and stress absorption capacity.

[0036] Creep resistance is another key factor in OLED mask applications, especially in manufacturing environments with high temperatures and long operating times. Figure 3 Creep resistance data for metallic and ceramic materials are provided, illustrating the behavior of these materials under long-term stress and thermal cycling.

[0037] The perforated metal layer 15 is composed of metals such as Invar, Nickel, and Super Invar, and may undergo creep deformation over time. Figure 3 The results show that metals such as nickel (0.6% strain / 1000 hours) and titanium alloys (0.5% strain / 1000 hours) are particularly sensitive to creep. During OLED manufacturing, the mask undergoes repeated heating and cooling cycles, causing the aperture metal layer 15 to gradually deform, thus affecting the accuracy of the aperture positions and OLED pixel alignment. However, the aperture composite layer 17 design by GS-FHM effectively reduces the effects of creep, improves the long-term stability of the mask, and ensures the consistency of OLED material deposition and high-resolution pixel alignment.

[0038] In contrast, the porous ceramic layer 16 exhibits near-zero creep, such as Figure 3 As shown, silicon nitride (Si3N4) and boron nitride (BN) have extremely high creep resistance (≤0.0001% strain / 1000 hours), ensuring dimensional stability under long-term use, and enabling the open-hole ceramic layer 16 to maintain precise opening shape and alignment accuracy during OLED material deposition.

[0039] However, although ceramic materials are highly resistant to creep deformation, they lack stress absorption capacity. Under mechanical impact, microcracks may form and propagate over time, affecting the aperture accuracy and long-term stability of the mask. During handling or removal of the glass substrate 13, the aperture ceramic layer 16 may be affected by localized stress, thus requiring further optimization of its structural strength.

[0040] like Figure 3 As shown, metallic materials are susceptible to creep, while ceramic materials are highly brittle. Therefore, it is difficult to simultaneously meet the requirements of long-term durability and mechanical stability of OLED masks by using either metallic or ceramic materials alone.

[0041] consider Figure 3 Based on strain hardening index (n value) and creep behavior data, GS-FMM and GS-FCM each have their own advantages and limitations in OLED material deposition applications, especially in high-resolution microOLED and large-area AMOLED applications, where both are affected by the properties of the materials themselves.

[0042] In GS-FMM, the open-cell metal layer 15 is composed of metals such as Invar, Super Invar, and Molybdenum, which have moderate strain hardening exponents (n≈0.2–0.4). Figure 3 As shown. This characteristic allows for stress redistribution, reducing the risk of sudden brittle fracture and giving GS-FMM high resistance to mechanical shock and handling stress. Furthermore, the metal gradually hardens under repeated stress, enhancing mechanical durability during OLED deposition. However, this n-value characteristic also leads to cumulative deformation, and the creep behavior of metals such as Nickel, Alloy 42, and Kovar is significant, affecting aperture stability. When the glass substrate 13 is removed, the release of internal stress may lead to plastic deformation, reducing aperture alignment accuracy.

[0043] In GS-FCM, the open-pore ceramic layer 16 is composed of materials such as silicon nitride (Si3N4) and alumina (Al2O3), which have extremely low n values ​​(~0.01), such as... Figure 3 As shown, no plastic deformation occurs, ensuring long-term aperture shape stability and maintaining high-precision aperture geometry. Furthermore, ceramic materials are virtually unaffected by creep, eliminating the risk of long-term deformation. However, ceramic materials lack stress redistribution capabilities, resulting in high brittleness and susceptibility to mechanical impact. In thin-film applications (≤10µm), even minute mechanical stresses during the removal of the glass substrate 13 can lead to crack formation and propagation over time, affecting mask life.

[0044] During OLED deposition, GS-FMM benefits from a moderate n-value, enabling stress redistribution, improving mechanical durability and stress absorption capacity, and reducing the risk of immediate breakage. However, creep deformation can still affect aperture stability, thereby impacting OLED pixel alignment and display uniformity. In contrast, GS-FCM maintains aperture precision due to its low n-value and extremely low creep, but its high brittleness may reduce mask lifespan with long-term use.

[0045] Figure 4 and Figure 5 Different structural variations of the GS-FHM are demonstrated. This mask combines an open-aperture metal layer 15 with an open-aperture ceramic layer 16 to balance structural stability and mechanical durability. These configurations enable the GS-FHM to adapt to various OLED manufacturing requirements, covering applications ranging from high-resolution microOLED panels to large-size AMOLED displays.

[0046] Figure 4 A shows a structure in which an open-hole metal layer 15 is situated on an open-hole ceramic layer 16, providing mechanical flexibility while ensuring shape stability through the support of the ceramic layer 16.

[0047] Figure 4 B shows the structure of the open-hole metal layer 15 formed on the electrode metal layer 14 by an electroforming process (EF), achieving higher mechanical strength and reducing thermal expansion mismatch. Electroforming technology is particularly suitable for low thermal expansion alloys such as Invar, and it is widely used in sheet fine metal masks (FMMs) to ensure excellent dimensional stability.

[0048] Figure 4 C illustrates a structure where an open-cell ceramic layer 16 sits atop an open-cell metal layer 15. This design enhances heat resistance while utilizing the mechanical flexibility of the open-cell metal layer 15 to improve structural stability.

[0049] These GS-FHM structures help reduce the deformation risk of pure metal masks (GS-FMM) and improve the brittleness of pure ceramic masks (GS-FCM), enabling them to maintain more stable mechanical properties and aperture accuracy during long-term use.

[0050] Figure 5 An advanced multilayer GS-FHM structure was demonstrated, in which the perforated metal layer 15 and the perforated ceramic layer 16 are arranged in a stacked manner to optimize mechanical properties and structural stability.

[0051] Figure 5 A shows that the perforated metal layer 15 is located between two perforated ceramic layers 16, which enhances shape retention and durability by reducing metal deformation, while maintaining the crack resistance of the ceramic layer 16.

[0052] Figure 5 B shows that the perforated ceramic layer 16 is sandwiched between two perforated metal layers 15, which improves heat resistance and mechanical flexibility, making it suitable for applications requiring higher thermal stability.

[0053] Figure 5 C shows a multi-layered, staggered structure in which perforated metal layers 15 and perforated ceramic layers 16 are alternately distributed to maximize mechanical strength, ensure uniform stress distribution and structural stability, and is particularly suitable for ultra-large-size OLED deposition applications.

[0054] GS-FHM has structural adaptability, and can be adapted to manufacturing conditions, mechanical durability requirements and thermal stability considerations by adjusting the composition of the perforated composite layer 17 according to the size and resolution requirements of OLED displays.

[0055] For small-sized, high-resolution microOLED displays, where sub-micron level aperture precision is crucial, the aperture ceramic layer 16 typically constitutes a large proportion to ensure aperture shape stability and prevent long-term deformation. In such applications, it is recommended to use... Figure 5 A and Figure 4 As shown in structure B, the perforated ceramic layer 16 is located on top of the perforated composite layer 17 to improve pattern accuracy and thermal stability. Furthermore, if a three-layer configuration is used, with the perforated metal layer 15 sandwiched between the two perforated ceramic layers 16, stress distribution can be optimized, balancing the brittleness of the ceramic with the stress absorption capacity of the metal, thus preventing premature mask failure due to handling stress.

[0056] For large-size AMOLED displays, due to the high requirements for long-term mechanical durability and flexibility, the perforated metal layer 15 typically constitutes a large proportion in this application to provide higher mechanical strength and resist large-area handling stress and deformation. It is recommended to use... Figure 5 The structure shown in B, where the perforated ceramic layer 16 is located between two perforated metal layers 15, prevents excessive deformation and allows stress release. Furthermore, if... Figure 5 The multi-layered staggered arrangement of C can further enhance the structural stability of large-size OLED masks and reduce the risk of mechanical failure caused by thermal cycling.

[0057] The design of the perforated composite layer 17 can be optimized by adjusting the relative thickness of the perforated metal layer 15 and the perforated ceramic layer 16, according to the structural and functional requirements of the mask. This ensures that the GS-FHM is suitable for different OLED manufacturing conditions, achieving a balance between mechanical durability, thermal stability, and stress absorption capacity. These variations allow the GS-FHM to flexibly adjust the ratio of the perforated metal layer 15 to the perforated ceramic layer 16 according to application requirements, adapting to the production needs of high-resolution microOLED panels or large-size AMOLED displays.

[0058] (Example 1) Figure 6 The manufacturing process of right-angle apertures in GS-FHM is demonstrated as a method for achieving high-precision patterning. Theoretically, to minimize the shading effect during material deposition from the back side, the aperture shape should have a negative cone angle, since the OLED substrate is located on top of the GS-FHM. A cone angle of 40 to 70 degrees is considered ideal. However, when the aperture composite layer 17 is sufficiently thin, the shading effect decreases, making right-angle apertures still suitable for high-precision deposition, providing an aperture option that meets process requirements.

[0059] The initial structure consists of a TFT-grade glass substrate 13, such as Corning Eagle XG or other display-grade glass with high thermal and chemical stability. The glass substrate 13 can be made of borosilicate glass, fused silica, or display-grade glass commonly used in TFT-LCD and AMOLED manufacturing, with a thickness ranging from 0.1 mm to 5.0 mm, to ensure a low coefficient of thermal expansion (CTE), high chemical resistance, and excellent mechanical strength, making it suitable for high-strength FMM supports.

[0060] A porous ceramic layer 16 is deposited above the glass substrate 13 using silicon nitride (Si3N4) deposited via low-pressure chemical vapor deposition (LPCVD) to ensure high density and mechanical strength. The thickness of this ceramic layer ranges from 0.01µm to 20µm, adjusted according to application, display size, and resolution requirements. Furthermore, other ceramic materials, such as alumina (Al2O3), zirconium oxide (ZrO2), silicon carbide (SiC), boron nitride (BN), and zirconium tungstate, can also be selected based on the mechanical and thermal stability requirements of the OLED evaporation process.

[0061] An open-cell metal layer 15, made of molybdenum (Mo), is formed on top of the open-cell ceramic layer 16 by sputter deposition. Molybdenum's low coefficient of thermal expansion provides excellent dimensional stability during high-temperature OLED evaporation processes. The thickness of the open-cell metal layer 15 ranges from 0.01µm to 20µm, ensuring suitability for different display resolutions and evaporation requirements. Alternatively, other low-CTE metals such as Invar, SuperInvar, Kovar, Alloy 42, nickel (Ni), tungsten (W), tantalum (Ta), and rhenium (Re) can also be used.

[0062] exist Figure 6 In step A, photoresist PR(1)18 is applied and patterned on the aperture metal layer 15 to define the aperture region. PR(1)18 is a positively cross-linked photoresist, which can achieve high-resolution patterning to accurately form the aperture. Subsequently, dry etching is used as the main etching method, especially reactive ion etching (RIE), using Cl2, BCl3 and Ar plasmas to etch the aperture to ensure that the aperture sidewalls are vertical and to avoid the positive cone angle effect that may be caused by wet etching.

[0063] exist Figure 6 In step B, photoresist PR(2)19 is applied as a full-area protective layer to protect the front side of the mask and prevent subsequent back-side etching from affecting it. Next, photoresist PR(3)20 is coated and patterned on the back side to define the etching area of ​​the display area 12 glass. The display area 12 of the glass substrate 13 is selectively removed by wet etching or dry etching.

[0064] like Figure 6As shown in Figure C, the glass substrate 13 is selectively removed from the back side in the non-display area 11 to form a self-supporting region supporting the aperture composite layer 17. The back-side etching profile (whether inclined or vertical) must be appropriately adjusted to avoid shadowing effects on adjacent apertures of the aperture composite layer 17 during OLED material deposition. If wet etching is used, hydrofluoric acid (HF) or buffered HF (BHF) can be used under heating conditions to achieve smooth removal of the glass substrate 13 and form a progressively inclined profile. If a near-vertical sidewall structure is required, deep reactive ion etching (DRIE) can be used in conjunction with SF6 or CF4 plasma. In some applications, wet and dry etching can also be combined to optimize the sidewall morphology of the glass substrate 13 and ensure that the final non-display area 11 does not cause shading interference to OLED pixel alignment.

[0065] exist Figure 6 In step C, all photoresist layers, including PR(2)19 and PR(3)20, are removed by O2 plasma ashing or NMP solvent removal. After this step, the final GS-FHM structure is formed, which includes a TFT glass substrate 13, an open-hole ceramic layer 16 and an open-hole metal layer 15. The materials can be adjusted according to application requirements to adapt to different high-precision OLED evaporation processes.

[0066] Figure 7 and Figure 8 Example 2 of the GS-FHM manufacturing process is described, demonstrating an alternative method for achieving right-angle or negative cone-angle openings based on etching process parameters.

[0067] exist Figure 7 In step A, an open-hole ceramic layer 16 and an open-hole metal layer 15 are deposited on a glass substrate 13. The open-hole ceramic layer 16 is made of silicon nitride (Si3N4) and is deposited by low-pressure chemical vapor deposition (LPCVD). The open-hole metal layer 15 is made of molybdenum (Mo) and is formed by sputtering deposition to ensure dimensional stability during the OLED evaporation process.

[0068] Material selection and coating methods can also be referenced. Figure 6 The perforated ceramic layer 16 can be replaced with materials such as alumina (Al2O3) or zirconium oxide (ZrO2), while the perforated metal layer 15 can be made of metals with low coefficients of thermal expansion, such as Invar, SuperInvar, tungsten (W), or rhenium (Re). The thickness of the perforated ceramic layer 16 and the perforated metal layer 15 ranges from 0.01µm to 20µm, depending on the application requirements, display size, and resolution.

[0069] exist Figure 7In step B, photoresist PR(2)19 is applied to the top surface of the aperture structure as a full-area protective layer. Subsequently, photoresist PR(3)20 is applied and patterned on the back side of the glass substrate 13 to define the etching range of the display area 12.

[0070] like Figure 7 As shown in Figure C, the glass substrate 13 undergoes selective etching from the back side in the non-display area 11 to preserve the structural region supporting the aperture composite layer 17. The sidewall morphology of the preserved glass substrate 13 area needs to be designed to effectively reduce the optical shading effect during OLED evaporation. If wet etching is used, HF or BHF can be used and operated under heating conditions to form a controllable beveled glass profile; if a vertical sidewall structure is required, deep reactive ion etching (DRIE) can be used in conjunction with SF6 or CF4 plasma. In some processes, wet and dry etching can also be combined to optimize the shape of the non-display area 11, balancing the mechanical support and optical clearance requirements of the aperture composite layer 17.

[0071] In applications requiring alignment marks, the alignment mark areas within the glass substrate 13 can be etched simultaneously in this step to ensure precise alignment in subsequent aperture patterning processes. However, since the glass substrate 13 is transparent to visible and infrared light, alignment can be performed through the glass substrate 13, so the glass substrate 13 in the alignment mark areas may not need to be etched. Furthermore, the etching method and timing of the alignment marks can be adjusted according to manufacturing requirements to adapt to different OLED mask process conditions.

[0072] Figure 8 Figure A illustrates the process of patterning the aperture structure using photoresist PR(4)21 to define the aperture area. Although not explicitly shown in the figure, alignment marks can also be patterned simultaneously to ensure accurate positioning in subsequent processes.

[0073] Wet etching can be used to form negative cone angle openings, while dry etching (such as reactive ion etching, RIE) is typically used for right-angle openings. However, deep reactive ion etching (DRIE) can control the sidewall angle by adjusting process parameters to form negative cone angle or right-angle structures, ensuring adaptability to different OLED processes.

[0074] The final GS-FHM structure includes an open-aperture composite layer 17, in which an open-aperture ceramic layer 16 is integrated with an open-aperture metal layer 15, providing good mechanical stability and ensuring that the opening shape is suitable for high-resolution OLED deposition, meeting the mask requirements under different process conditions.

[0075] Figure 9 and Figure 10 Example 3 illustrates the GS-FHM manufacturing process, which is similar to Example 2, allowing for the formation of right-angle or negative cone-angle openings by adjusting etching process parameters. (Compared to Example 1...) Figure 6Compared to this method, this method is... Figure 10 B adds an extra cone angle adjustment step to control the sidewall angle of the opening.

[0076] exist Figure 9 In step A, an open-hole ceramic layer 16 and an open-hole metal layer 15 are deposited on a glass substrate 13. The open-hole ceramic layer 16 is made of silicon nitride (Si3N4) and is deposited by low-pressure chemical vapor deposition (LPCVD). The open-hole metal layer 15 is made of molybdenum (Mo) and is formed by sputtering deposition to ensure dimensional stability in the OLED evaporation process.

[0077] For material selection, coating method, and thickness, please refer to [reference needed]. Figure 6 The perforated ceramic layer 16 can be replaced with materials such as alumina (Al2O3) or zirconium oxide (ZrO2), while the perforated metal layer 15 can be made of metals with low coefficients of thermal expansion, such as Invar, SuperInvar, tungsten (W), or rhenium (Re). The thickness of the perforated ceramic layer 16 and the perforated metal layer 15 ranges from 0.01µm to 20µm, depending on the application requirements, display size, and resolution.

[0078] exist Figure 9 In B, photoresist PR(1)18 is applied and patterned to define the aperture area. The aperture metal layer 15 and aperture ceramic layer 16 are then etched by dry etching, including reactive ion etching (RIE) using Cl2, BCl3 and Ar plasma to ensure that the aperture shape is clear and the sidewalls are vertical.

[0079] exist Figure 9 In C, a protective photoresist PR(2)19 is applied to the front side of the aperture structure as a full-area protective layer, and a photoresist PR(3)20 is applied and patterned on the back side of the glass substrate 13 to define the glass etching area.

[0080] In applications requiring alignment marks, the alignment mark areas of the glass substrate 13 can be etched simultaneously in this step to ensure accurate alignment in subsequent processes. However, depending on manufacturing requirements and alignment methods, the alignment mark areas of the glass substrate 13 can also remain unetched for optical alignment via the glass substrate 13.

[0081] Figure 10 Step B is a key step in Example 3; this step is used to adjust the cone angle of the opening. Figure 6In comparison, this method adds full-exposure dry etching and does not use an aperture photoresist mask. By precisely controlling the etching rate and selectivity, the photoresist PR(2)19 can be gradually consumed and the exposed aperture ceramic layer 16 can be etched to achieve a controllable reverse cone angle aperture structure. In addition, if wet etching is used, the sidewall angle of the aperture ceramic layer 16 can be further controlled by adjusting the etching conditions and time to ensure the best OLED evaporation effect.

[0082] exist Figure 10 In C, all photoresist layers, including PR(2)19 and PR(3)20, are removed by O2 plasma ashing or NMP solvent removal. The final GS-FHM structure includes an open-hole composite layer 17, in which an open-hole ceramic layer 16 is integrated with an open-hole metal layer 15. After optimization, it is suitable for high-precision OLED evaporation processes and the cone angle of the openings can be adjusted.

[0083] Figure 11 and Figure 12 Example 4 of the GS-FHM manufacturing process is shown, which differs from the previous examples by using electroforming (EF) technology to form the open-hole metal layer 15 instead of a sputtering process. Due to the use of electroforming, Invar is chosen as the material for the open-hole metal layer 15 instead of molybdenum (Mo) because Invar exhibits superior mechanical strength and stability during electroforming. Furthermore, Figure 10 The aperture cone angle adjustment technology of B is also applicable to this embodiment to further control the aperture shape.

[0084] exist Figure 11 In step A, an open-cell ceramic layer 16, made of silicon nitride (Si3N4), is deposited on the glass substrate 13 via low-pressure chemical vapor deposition (LPCVD) to provide a stable substrate to support subsequent electroforming processes. Next, an electrode metal layer 14 is deposited over the open-cell ceramic layer 16. This layer can be formed by sputtering or vapor deposition to ensure appropriate adhesion and conductivity to facilitate the electroforming process.

[0085] exist Figure 11 In step B, a patterned photoresist PR(5)22 is applied to define the aperture region. This step also simultaneously patterns alignment marks to ensure precise alignment in subsequent processes. An electroforming process is then performed to grow an Invar aperture metal layer 15 on the exposed electrode metal layer 14, giving it controllable thickness and high stability. Because the photoresist PR(5)22 has a positive cone angle, the electroformed Invar aperture layer 15 naturally forms a reverse cone angle, conforming to the desired aperture shape.

[0086] exist Figure 11In step C, after the electroforming process is completed, PR(5)22 is removed, leaving a precisely defined Invar aperture structure. The final GS-FHM aperture composite layer 17 includes an electroformed Invar aperture metal layer 15, an aperture ceramic layer 16, and a residual electrode metal layer 14.

[0087] exist Figure 12 In A, similar to Example 3, the alignment mark area of ​​the glass substrate 13 is etched to ensure that the alignment marks can be accurately transferred to subsequent processes. At this time, a full-area photoresist PR(2)19 is applied as a protective layer, followed by back glass etching. Wet etching (HF, BHF) or dry etching (RIE / DRIE, SF6, CF4 plasma) can be used to remove the glass substrate 13 of the display area 12.

[0088] exist Figure 12 In section B, the hole taper angle adjustment process is implemented. Figure 10 B) Adjusting the aperture angle. Since no aperture photoresist mask is used in this step, dry etching can be performed on the entire area. By gradually consuming PR(3)20 and etching the exposed aperture ceramic layer 16, a reverse cone angle is naturally formed. In addition, by controlling the wet etching conditions and time, the aperture ceramic layer 16 can be further adjusted to produce a negative cone angle aperture, thereby improving the OLED evaporation accuracy. To ensure the consistency of the aperture outline, the cone angle of the aperture ceramic layer 16 and the electrode metal layer 14 must match that of the electroformed aperture metal layer 15.

[0089] exist Figure 12 In step C, all remaining photoresist layers are removed by O2 plasma ashing or NMP solvent, ultimately forming a complete GS-FHM structure. The final structure includes an electroformed Invar open-hole metal layer 15, an open-hole ceramic layer 16, and an electrode metal layer 14, providing high mechanical stability and precise taper angle control, suitable for high-resolution OLED evaporation processes.

[0090] Although each step in the manufacturing process of Examples 1 to 4 is not fully elaborated, all examples maintain consistency in material selection, deposition method, etching process and thin film structure to ensure optimized high-precision OLED evaporation performance.

[0091] The glass substrate 13 is made of borosilicate glass, fused silica, or TFT-grade display glass, such as Corning Eagle XG, materials widely used in TFT-LCD and AMOLED manufacturing. The thickness of the glass substrate 13 ranges from 0.1 mm to 5.0 mm, ensuring mechanical strength, thermal expansion control, and chemical stability according to application requirements.

[0092] The open-cell ceramic layer 16 is primarily composed of silicon nitride (Si3N4) and is prepared via LPCVD (low-pressure chemical vapor deposition) to ensure high density and high mechanical strength. Depending on the thermal and mechanical performance requirements, alternative materials such as alumina (Al2O3), zirconium oxide (ZrO2), silicon carbide (SiC), boron nitride (BN), or zirconium tungstate can also be used. The open-cell ceramic layer 16 can be prepared using LPCVD, PECVD (plasma-enhanced chemical vapor deposition), or ALD (atomic layer deposition), with a thickness ranging from 0.01 µm to 20 µm to ensure structural stability and compatibility with the glass substrate 13.

[0093] The material selection for the aperture metal layer 15 depends on the manufacturing method. For sputtering deposition, molybdenum (Mo) is preferred due to its low coefficient of thermal expansion and high mechanical strength. Depending on the stability requirements of high-temperature OLED evaporation, Invar, SuperInvar, tungsten (W), rhenium (Re), tantalum (Ta), nickel (Ni), or alloy 42 can also be used as alternative materials. For electroforming (EF) deposition processes, Invar is the preferred material, as shown in Example 4, due to its excellent mechanical stability during electroforming. The aperture metal layer 15 can be prepared by sputtering, ALD, evaporation, or electroforming, with a thickness ranging from 0.01 µm to 20 µm to ensure precise pattern retention and dimensional stability during OLED material deposition.

[0094] Electrode metal layer 14 is used only in Example 4 for electroforming and is disposed below the aperture metal layer 15 as a conductive base layer for electroforming aperture metal layer 15. This layer is deposited by sputtering or vapor deposition, and the material can be selected from nickel (Ni), copper (Cu), or chromium (Cr) to ensure proper adhesion and conductivity, thereby providing uniform electroforming growth and mechanical reliability.

[0095] The aperture etching method is selected based on the desired aperture profile. Reactive ion etching (RIE) using Cl2, BCl3, and Ar plasmas can form right-angle apertures, as shown in Example 1. Figure 6 As shown in Example 3. Deep reactive ion etching (DRIE) uses SF6 or CF4 plasma with an adjustable cone angle. Figure 10 As shown in B). Wet etching using HF or BHF can also form negative cone angle openings, as shown in Examples 3 and 4.

[0096] The glass etching process for the display area 12 and the alignment marks is the same in all embodiments. Wet etching (HF, BHF) or dry etching (RIE / DRIE, SF6, CF4 plasma) can be used to selectively remove the glass substrate 13, ensuring precise aperture alignment. During glass removal, the glass substrate 13 may be simultaneously etched in the alignment mark area, or left unetched as required by the process, to ensure precise positioning for OLED deposition and subsequent process steps, as described in claim 6.

[0097] Photoresist layers PR(1)18, PR(2)19, PR(3)20, PR(4)21 and PR(5)22 are used for different masking steps. Positive crosslinked photoresist is used for aperture patterning, while full-area photoresist coating is used for back-side etching protection.

[0098] The final GS-FHM structure includes an open-cell composite layer 17, which integrates an open-cell ceramic layer 16 and an open-cell metal layer 15, and additionally includes an electrode metal layer 14 during the electroforming process. This structure ensures high mechanical stability, precise opening control, and optimized OLED deposition accuracy, as described in claims 2-5.

[0099] Symbol Explanation 11: Non-display area 12: Display area 13: Glass substrate 14: Electrode metal layer 15: Perforated metal layer 16: Perforated ceramic layer 17: Open-cell composite layer 18: PR(1) 19: PR(2) 20: PR(3) 21: PR(4) 22:PR(5).

Claims

1. A glass substrate-supported fine composite mask (GS-FHM) for OLED display manufacturing, comprising: —A glass substrate located in the non-display area, used to provide structural support for the mask; — An open-cell composite layer located in the display area forms openings for material deposition; The perforated composite layer comprises at least one perforated metal layer and at least one perforated ceramic layer to enhance structural strength, shape retention and mechanical stability, ensuring suitability for various OLED display applications.

2. The fine composite mask supported by a glass substrate according to claim 1, wherein the glass substrate is selected from borosilicate glass, fused silica, or TFT-grade display glass, including Corning Eagle XG, and has a thickness ranging from 0.1 mm to 5.0 mm to ensure structural integrity and chemical stability during the OLED deposition process.

3. The fine composite mask supported on a glass substrate according to claim 1, wherein the coefficient of thermal expansion (CTE) of the open-pore ceramic layer is less than 20 ppm / K, and the open-pore ceramic layer is selected from silicon nitride (Si3N4), alumina (Al2O3), zirconium oxide (ZrO2), silicon carbide (SiC), boron nitride (BN) or zirconium tungstate, and is prepared by LPCVD, PECVD or ALD, with a thickness ranging from 0.01 µm to 20 µm, to ensure structural stability and compatibility with the glass substrate.

4. The fine composite mask supported on a glass substrate according to claim 1, wherein the coefficient of thermal expansion (CTE) of the aperture metal layer is less than 20 ppm / K, and the aperture metal layer is selected from molybdenum (Mo), Invar, SuperInvar, tungsten (W), rhenium (Re), tantalum (Ta), nickel (Ni) or alloy 42, and is prepared by sputtering, ALD, evaporation or electroforming, with a thickness ranging from 0.01 µm to 20 µm to ensure accurate pattern retention and dimensional stability during OLED material deposition.

5. The glass substrate-supported fine composite mask according to claim 4 further includes an electrode metal layer disposed below the aperture metal layer, wherein the coefficient of thermal expansion (CTE) of the electrode metal layer is less than 20 ppm / K and its thickness ranges from 0.01 µm to 20 µm to ensure uniform electroforming growth and mechanical reliability.

6. The fine composite mask supported by the glass substrate according to claim 1, further comprising alignment marks patterned on the glass substrate, wherein the glass substrate is etched in the alignment mark area during glass removal to ensure precise positioning of OLED deposition and subsequent process steps.

7. The fine composite mask supported by a glass substrate according to claim 1, wherein the aperture composite layer comprises apertures having a right angle or a negative cone angle shape, wherein the right angle aperture has a vertical sidewall, and the top opening of the negative cone angle aperture is smaller than the bottom opening to ensure the optimal deposition angle of OLED manufacturing materials.

8. The glass substrate-supported fine composite mask according to claim 1, comprising: — An open-hole composite layer deposited on a glass substrate, with openings formed by photoresist patterning and etching from the front side; The glass substrate for the display area is selectively etched and removed from the back side.

9. The fine composite mask supported on a glass substrate according to claim 8, wherein, after patterning, a negative cone angle opening is formed by further etching an opening composite layer from the back side.

10. The glass substrate-supported fine composite mask according to claim 1, comprising: — An open-hole composite layer deposited on a glass substrate, with openings formed by photoresist patterning and etching from the back side; The glass substrate for the display area is selectively etched and removed from the back side.

11. The glass substrate-supported fine composite mask according to claims 1 and 5, comprising: —A porous ceramic layer and an electrode metal layer are deposited on a glass substrate, and the openings are formed by photoresist patterning and etching from the front side; —An open-hole metal layer is formed on the electrode metal layer by electroforming, the open-hole metal layer having a negative cone angle shape; —The glass substrate for the display area is selectively etched and removed from the back side; After the glass substrate in the display area is removed, the negative cone angle shape of the opening is adjusted by further etching the opening ceramic layer and electrode metal layer from the back side.

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